Rick...you actually had -20 here? Wow...I don't remember it getting down even to 0 in PA...maybe too young to notice. We probably had better insulated homes and a good heat system. The house here wouldn't get above 58 degrees for a whole day and I finally turned off the heat pump...which seemed to just bring in more cold air and used the small electric heaters we have. I lived in my coat indoors. Managed to get plastic up over 2 doors that didn't need used...and the house came up a good 5 degrees. The greenhouse was about the same as outside temp...the favas are still alive today...not real perky, but alive!